(Default) Selects the specified display as the current scrolling
display. This is the default display for the SCROLL, MOVE,
and EXPAND commands. Although any display can have the scroll
attribute, you can use only the MOVE and EXPAND commands (not the
SCROLL command) with the PROMPT display.
If you do not specify a display, the current scrolling display is
unselected and no display has the scroll attribute.
By default, for all languages except MACRO-32, the SRC display
has the scroll attribute. If the language is set to MACRO-32, the
INST display has the scroll attribute by default.